Conventionally a device for low-pressure casting has been proposed. The device does not have a complicated structure. It allows air in a mold, a tube for casting (a stalk), and a holding furnace to be effectively replaced with non-oxidizing gas. The device comprises a holding furnace that is sealed almost airtightly, a means for supplying non-oxidizing gas to the holding furnace, a stalk by which the holding furnace communicates with a mold, and a means for switching the opening of the stalk at the holding furnace side to the position for casting or to the position for replacing a mold. At the position for casting, the opening is immersed in molten metal. At the position for replacing, at least a part of the opening is over the surface of the molten metal in the holding furnace. Non-oxidizing gas is supplied to the holding furnace when the stalk is shifted to the position for replacing. Thus the air in the holding furnace, the stalk, and the mold is replaced with the non-oxidizing gas (see Japanese Patent Laid-open Publication No. 2000-42715).